An organic electroluminescence device (referred to below as “organic EL device”) which uses an organic electroluminescence device realizes light emittance in each color in the visible light band by selecting an organic material or adopting an appropriate structure of an organic EL device. As a result, the development of display devices or lighting appliances using organic EL devices is progressing.
An organic EL display device is provide with an organic EL device in each pixel and the organic EL device in each pixel is connected to a transistor and light emittance is controlled via the transistor. The organic EL device us formed in a device substrate formed with transistor. An interlayer insulation layer is provided between the organic EL device and transistor in the pixel structure, and one electrode which forms the organic EL device and the source/drain of the transistor are electrically connected in a contact hole formed in the insulation layer.
An organic EL display device includes a pixel array provided with these pixels in a matrix shape, the light emitted from the organic EL device is emitted to the side of a device substrate or an opposing substrate provided facing the device substrate and thereby a display screen is formed on that surface.
The organic EL device is provided with a layer (referred to below as “organic EL layer”) including an organic electroluminescence material between a pair of electrodes called an anode and cathode. As one example, the organic EL layer is formed by stacking a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and electron injection layer and the like.
A method is known for arranging a concave shaped bank layer as a component for sectioning each pixel region provided with this type of organic EL layer and forming an organic EL layer using an inject method within a region enclosed by the bank layer. However, when miniaturization of a pixel progresses in order to realize high definition of a display device, a problem occurs whereby the material solution of the organic EL layer does not spread uniformly within the region enclosed by the bank layer and easily flows out to an adjacent pixel region. The organic EL display device disclosed in the publication of Japanese Patent No. 3328297 discloses a process for providing water repelling properties and lyophilic properties by a surface treatment of a bank layer using a plasma treatment or infrared irradiation treatment and the like.
The conventional organic EL display device described above requires a smaller liquid drop size than the aperture width of a pixel when forming an organic EL layer using and inkjet method. However, in recent organic EL display devices, since miniaturization of pixels is progressing further, there is a problem whereby the burden on the manufacturing process increases with further miniaturization of the size of liquid drops and an increase in pixel numbers. In addition, with the progress in miniaturization of pixels, when a conductive material such as a hole injection layer or charge generation layer (CGL) which form an organic EL device is provided between a plurality of pixels, a leak current flows between adjacent pixels.